If Boston gets a 2nd title, I think that will probably push Brown in. If they don't get the 2nd title, I think Brown needs a few more seasons like this one where he has the mega stats and will be on an All NBA Team.
I'm going to presume that he makes the All-Star team and an All-NBA team this season.
That would leave him with 5x All-Star, 2x All-NBA, 1 title, 1 Finals MVP, 19.5 ppg / 5.4 rpg career averages
I think that would make him a borderline case.
If you add just two more seasons as an All-Star, even without a title or another All-NBA team, I think he'd basically be a lock. But, that's a guess. Does anybody know: is there any 7x All-Star, 2x All-NBA player that won a title that isn't in the Hall?
EDIT: The only 7x All-Star who is eligible that hasn't been selected for the HOF is Larry Foust, who was actually an 8x All-Star. Eligible 6x All-Stars not in are Larry Costello (in as a contributor, not as a player), Shawn Kemp, Amare Stoudemire and Jermaine O'Neal. So, JB seemingly just needs another couple of good seasons.